Means for making abrasive material



Nov. 24, 1936. KANN 2,062,093

MEANS FOR MAKING ABRASIVE MATERIAL Filed Jan. 9, 1935 2 Sheets-Sheet 1 INVENTOR.

ATTORNEY.

Nov; 24, 1936, G. H. KANN MEANS FOR MAKING ABRASIVE MATERIAL Filed Jan. 9, 1955 2 Sheets-Sheet 2 INVENTOR.

Guslave H K 0 1777. 2 M

WI ATTORNEY.

Patented Nov. 24, 1936 UNITED STATES PATENT OFFICE MEANS FOR MAKING ABRASIVE MATERIAL Application January 9, 1935, Serial No. 1,017

6 Claims. (CI. 83-91) This invention relates to processes and apparatus for producing abrasive material and particularly for producing shot, grit and the like for abrasive purposes from metal.

Heretofore, shot for abrasive purposes has been produced from hard metal such as iron or steel by methods and apparatus involving melting of the metal and then breaking it up into molten particles and chilling the particles to solidity. Such processes and apparatus have been deficient in that the shot produced thereby has been variable of size, shape and hardness; and it has therefore been diflicult or impossible to produce at will a desired quantity of shot having specified abrasive properties for specified abrasive purposes.

Among the objects, therefore, of the present invention are:

To provide an improved process and apparatus for producing metal shot for abrasive purposes;

To provide a method and process whereby abrasive metal shot can be produced and at an improved degree of uniformity of size, shape and hardness;

To provide a method and apparatus for producing abrasive metal shot of improved abrasive shape;

To provide a method and means for producing abrasive metal shot of improved hardness;

To provide a method and apparatus for producing metal abrasive shot which will be simple and economical to construct and operate and having improved means for rendering it continuous in operation.

Other objects will be apparent to those skilled in the art to which my invention appertains.

My invention is fully disclosed in the following description taken in connection with the accompanying drawings, in which:

Fig. 1 is a vertical longitudinal sectional view of an apparatus embodying my invention and whereby the process of my invention may be practiced;

Fig. 2 is a cross-sectional view taken approximately from the plane 22 of Fig. 1.

Referring to the drawings, I have shown at I a housing or chamber wherein the apparatus embodying my invention may be housed or enclosed, and in the preferred embodiment, the chamber I is in the form of a vertical hollow cylinder and the-wall thereof is made from relatively thick sheet metal or plate. Secured upon the inner wall of the chamber I is a. pair of vertically spaced bearing brackets 2 and 3. A channel-form arm 4, generally horizontally disposed, is mounted at one end to swing in a horizontal plane by a bearing construction comprising upper and lower trunnions 5 and 6 rigidly connected to the arm 4 and having rotational bearing in bores I and 8 in the brackets 2 and 3, respectively.

A vertical shaft 9 is rotatably mounted in corresponding bearing bores in the. trunnions 5 and 6 and supported against downward displacement by a collar ID on the shaft. Below the bracket 3 the shaft has thereon a bevel gear I I meshed with a bevel gear I2 on an outwardly horizontally extending shaft I3 rotatably supported in a bearing I4 on the bracket 3. outwardly, the shaft I3 has a gear I5 thereon meshing with a pinion I6 on the shaft of a motor I! supported on a bracket I8 secured to the outer wall of the chamber I.

A pair of spaced bearings I9 and on the arm 4 rotatably support a shaft 2I having a bevel gear 22 on one end thereof meshed with a bevel gear 23 on the shaft 9, and at its other end having a bevel gear 24 meshed with a bevel gear 25 on a short shaft 26 extending upwardly through the arm 4 and supported in a suitable bearing therein.

On the inner end of the arm 4 and supported thereon and connected to the shaft 26' is a head 21 comprising an upwardly open shallow cup receptacle 28 in which is seated a disc 29 preferably formed from refractory material such as boron-carbide. Preferably also the upper face 30 of the disc 29 is upwardly concave and rotates on a vertical axis of symmetry determined by the shaft 26.

By the foregoing construction, it will now appear that when the motor I1 is energized, it will drive the shaft I3 through the gears I6 and I5; and by the gears I2 and II, shaft 9, gears 23 and 22, shaft 2|, gears 24 and 25, shaft 26, and head 21, will rotate the disc 29 at a suitable predetermined speed to be referred to.

By means of a controller, for example, a rheostat type of controller, indicated at 3|, the speed of the motor I! may be adjusted to rotate the disc 29 at a suitable speed for purposes to be described.

At 32 is indicated in simplified form a cupola for melting metal and at 33 a discharge spout therefrom. These parts can be constructed in any suitable manner well known in the art so that a flow of molten metal from the cupola 32 may be controlled and by means of the spout 33 caused to flow therefrom in a stream 34 and impinge substantially upon the center of the disc 29.

The lower part of the chamber I is sealed by a bottom 35 to provide a well or pool of water 36.

The operation of the apparatus thus far described is as follows: The motor I1 is operated to rotate the disc 29 at a suitable predetermined speed and molten metal such as steel or iron is caused to flow through the spout 33 and impinge upon the center of the rotating disc 29. The molten metal is immediately caused by centrifugal force to flow radially outwardly from the center of the disc 29 in all directions and to be thrown therefrom. As the metal flows toward the edge of the disc 29, its velocity increases under the impulsion of the centrifugal force, and the stream becomes more and more shallow and of greater and greater area, as it spreads out over the disc.

As is well known, molten metal has a considerable surface tension which tends to prevent the metal from being reduced to less than a certain minimum thickness. If the metal is forced by the speed of the disc 29 to tend to make a thinner than the minimum layer of liquid metal, the metal will break up into generally globular particles of molten metal, the velocity and the surface tension combining to this result, one opposing the other. The particles of molten metal leaving the disc are thrown therefrom outwardly into the space in the chamber surrounding the disc and fall through the air by gravity into the water 36. The globular particles of fluid metal are thus cooled and upon contacting with the water are chilled and thereby tempered or hardened. The water can be continually cooled by supplying cool water thereto through a pipe 31 and withdrawing it through a pipe 38.

When the liquid metal breaks up into particles, the particles roll on the surface of the disc and leave the disc with a whirling or spinning motion which together with action of surface tension gives them a spherical or substantially spherical form, and the particles cool and solidify in this form, producing a superior abrasive material.

By making the disc 29 slightly concave, the particles of molten metal will be first thrown upwardly as indicated at 39 and then will fall downwardly as indicated at 40 and may thus be given a longer time contact with the air for a given size of apparatus; also a saving in the diameter of the chamber I may thereby be effected since the particles will be thrown a lesser distance from the center of the disc 29. 1

The bottom 35 of the chamber may be inclined outwardly and extended beyond the wall of the chamber I as at 41 to provide a water sealed opening 42 to give access to the shot which accumulates on the bottom 35 for removal of the same. Any means to remove the shot may be utilized such as a screw conveyor, or the shot may be raked out of the pool of water by hand tools.

By varying the speed of the motor I1, the rotational speed of the disc 29 may be varied to cause the molten. metal to break up into suitable particles. The disc 29 may be large enough in diameter to cause the particles to be completely formed thereon before leaving the periphery of the disc, or the disc may be of smaller diameter and the impulsion given to the molten metal as it leaves the edge of the disc may be relied upon to continue the stream-thinning action and to cause the stream to break up into particles after it leaves the edge of the disc. The effect of encountering the air as ,the molten metal leaves the disc tends still further to break it up into particlcs.

By means of the apparatus above described, I have found that by adjusting the speed of the disc 29 the shot deposited in the water 36 will have a high degree of uniformity of size, spheaoeaoos ricity and hardness with the minimum of waste pieces or particles.

In cases where it is desired to operate the apparatus substantially continuously, a plurality of cupolas and spouts may be provided. Another such cupola 32a and spout 33a are indicated in broken lines in Fig. 1. Under long continued operation, the disc 29 may deteriorate under the action of the intense heat of the molten metal continuously flowing thereon; and to avoid the necessity of shutting down the process, the construction illustrated is provided. Another arm 4a is provided pivotally supported on brackets 2a and 3a, and during the operation of the disc 29, the arm 4a is maintainedin an out-of-the-way position byswinging it around into the position shown in Fig. 2, .the construction involving the trunnions 5 and 6 and the bearing bores I and 8 described in connection with the arm 4 being provided also for the arm 4a. When it becomes necessary to renew or repair the disc 29, it and its arm 4 are swung around to the broken line position shown in Fig. 2 and the disc 29a and its arm 4a are swung inwardly to substitute the disc 29a for the disc 29, and the process may go on. Suitable openings 43 are provided in the wall of the chamber I through which the ends of the arms 4 and 4a and the discs 29 and 29a may be projected to bring them into positions outside of the chamber I to give access thereto, and the openings 43 normally may be closed by doors 44-44. The means for supporting and driving the disc 29a may be identical with those for driving the disc 29 and a description thereof is deemed unnecessary in view of the showing of the drawings.

My invention is not limited to the exact details of construction shown and described. Modifications and changes may be made therein without departing from the spirit of my invention, and my invention comprehends all such modifications and changes which are embraced within the scope of the appended claims. And while I have described my invention as for making abrasive shot, it will be understood that this term is inclusive of shot, grit and the like for abrasive purposes.

I claim:

1. In an apparatus for making metal shot, grit and the like, for abrasive purposes, a rotatable element having a generally horizontal surface rotatable about a center of rotation, means for melting metal and discharging it in a stream upon the said surface, an arm rotatably supporting the element, a support for the arm on which it may swing about a vertical axis to remove the rotatable element laterally to a lateral position from a normal metal stream receiving position and return it thereto, transmission means transmitting power along the arm for rotating the rotatable element when in either of said positions and the arm and transmission means being disposed wholly below the said surfaces of the rotatable elements.

2. In an apparatus for making metal shot, grit and the like for abrasive purposes, a plurality of rotatable elements having each a generally horizontal surface rotatable about a center of rotation, an arm rotatably supporting each rotatable element, a support for each arm upon which the arm may swing about a vertical axis to move the respective rotatable elements laterally alternately to a common position or remove them therefrom to a lateral position, transmission means for transmitting power along the arms for -a,oea,oes v disposed wholly below the said surface of the 1-0- rotatable about a center of rotation, means for melting metal and discharging it in a stream substantiallyiupon the rotational center of the surface, an arm rotatably supporting the element, a support for the arm on which it may swing to remove the rotatableelement laterally from a normal metal stream receiving position and return it thereto, means for rotating the rotatable element when'in said normal position, a wall encircling the rotatable element and swinging; arm, an aperture in the wall through which the rotatable element may be projected by the swinging arm to give access thereto externally of the wall.

4. In an apparatus for making metal shot, grit and the like for abrasive purposes, a rotatable element having a generally horizontal surface rotatable about a center of rotation, means for melting metal and discharging it in a stream upon the said surface, a movable support for the rotatable element movable to remove the rotatable element laterally to a lateral position from a normal metal stream receiving position and return it thereto, power transmission means carried by the movable support for rotating the rotatable element when in either of said positions and the movable support and transmission means being tatable elements.

5. In an apparatus for making metal shot, grit and the like for abrasive purposes, a plurality of rotatable elements having each a generally horizontal surface rotatable about a center of rotation, a movable support for each element movable to move the respective rotatable elements laterally alternately to a common position or to remove them therefrom to lateral positions, transmission means for transmitting power for rotating the respective rotatable elements when in either of said positions, means for melting metal and discharging it in a stream upon the respective surfaces of "the rotatable elements when in said normal position and the movable supports and.

transmission means being disposed wholly below the said horizontal surfaces of the rotatable elements.

'6. In an apparatus for making metal shot and the like for abrasive purposes, a walled housing having a pool of water in the lower portion thereof, a laterally swingable arm supported upon the housing wall above the water in the pool, a disc rotatable on a vertical axis supported on the arm swingable therewith to dispose the disc in a plurality of positions in the housing, a stationary source of power, transmission means to transmit power from the source along the arm to the disc to rotate it in all of said plurality of positions, means to discharge a stream of molten metal upon the disc when in a predetermined position and the arm and transmission means be'ing jdisposed wholly below the said disc.

GUSTAVE HJKANN. 

